Volume 75, Issue 2, Pages 695-703 (August 1998) Imaging of the Surface of Living Cells by Low-Force Contact-Mode Atomic Force Microscopy  Christian Le Grimellec, Eric Lesniewska, Marie-Cécile Giocondi, Eric Finot, Véronique Vié, Jean-Pierre Goudonnet  Biophysical Journal  Volume 75, Issue 2, Pages 695-703 (August 1998) DOI: 10.1016/S0006-3495(98)77559-9 Copyright © 1998 The Biophysical Society Terms and Conditions

Figure 1 Imaging at low-magnification of living CV-1 cells by low-force contact-mode AFM. (A (height mode) and B (deflection mode; z range 5nm)) 80-μm xy scan of a group of cells. Scan rate: 1.2Hz. (C (height mode) and D (deflection mode; z range 3nm)) 30-μm xy scan of the same group of cells. The box in B shows the region chosen for the 30-μm scan. Scan rate: 1.8Hz. (E and F) Force versus distance curve corresponding to the imaging of A–D, respectively. Biophysical Journal 1998 75, 695-703DOI: (10.1016/S0006-3495(98)77559-9) Copyright © 1998 The Biophysical Society Terms and Conditions

Figure 2 Force adjustment before scanning. Representative experiment showing the evolution of cantilever deflection (upper diagram) and force (lower diagram) versus distance curves obtained at the center of a cell (above the nucleus area), using the procedure described in the text. Cantilever spring constant: 0.01N/m. z scan rate: 1Hz. Biophysical Journal 1998 75, 695-703DOI: (10.1016/S0006-3495(98)77559-9) Copyright © 1998 The Biophysical Society Terms and Conditions

Figure 3 Effects of a 75-fold variation in the scanning force on the topography of living CV-1 cells. Height mode. Scan size: 20μm. Thin arrows: thin filaments. Thick arrow: damaged area. Section shows the height profiles obtained as a function of the scanning force, along a scan line indicated in black. Relative height position of curves was standardized, using the glass support as a reference. Scan rate: 1.2Hz. Biophysical Journal 1998 75, 695-703DOI: (10.1016/S0006-3495(98)77559-9) Copyright © 1998 The Biophysical Society Terms and Conditions

Figure 4 Ten-micron scan of the surface of CV-1 cells and corresponding section and force versus distance curve. Horizontal distances between the pairs of green, black, and red arrows were 293, 195, and 118nm, respectively. Scan rate: 2Hz. Biophysical Journal 1998 75, 695-703DOI: (10.1016/S0006-3495(98)77559-9) Copyright © 1998 The Biophysical Society Terms and Conditions

Figure 5 Three-micron scan of the surface of CV-1 cells and corresponding force versus distance curve. Scan rate: 2Hz. Biophysical Journal 1998 75, 695-703DOI: (10.1016/S0006-3495(98)77559-9) Copyright © 1998 The Biophysical Society Terms and Conditions

Figure 6 Topographical modification between successive scans. Scan size: 2μm. Scan force: 80pN. Scan rate: 2.5Hz. Biophysical Journal 1998 75, 695-703DOI: (10.1016/S0006-3495(98)77559-9) Copyright © 1998 The Biophysical Society Terms and Conditions

Figure 7 High-magnification imaging of the cell surface at low force. (A) Two-micron scan of the surface of living CV-1 cells (height mode, raw image). The presence of tiny particles is visible on the lower left corner of the image. Scan force: 60pN; scan rate: 1.2Hz. (C) One-micron electronic zoom of the lower left corner, identified by a box, of A. B and D correspond to A and C, respectively, after low-pass filtering. (E) Section analysis of C. Horizontal distances between the pairs of green, red, and black arrows were 17.6, 49.0, and 15.7nm, respectively. The vertical distance between the pair of red arrows was 7.3nm. Biophysical Journal 1998 75, 695-703DOI: (10.1016/S0006-3495(98)77559-9) Copyright © 1998 The Biophysical Society Terms and Conditions

Figure 8 Submicron scan of the surface of living CV-1 cells. Scan size: 475nm. Scan rate: 2Hz. (A) Height image (low-pass filtered). z range: 10nm. (B) Friction image (low-pass filtered). z range: 0.025V. (C) Section analysis of A. Vertical distances between the pairs of green and red arrows were both 1.9nm. Horizontal distance between the pair of black arrows: 7.2nm. (D) Section analysis of B. Horizontal distances between the pairs of green, red, and black arrows were 7.4, 5.6, and 14.8nm, respectively. (E) Corresponding force versus distance curve. Biophysical Journal 1998 75, 695-703DOI: (10.1016/S0006-3495(98)77559-9) Copyright © 1998 The Biophysical Society Terms and Conditions